Sleeping adequately, am I geting enough sleep?

Hi, lately I have been having sleeping difficulties but am not in at least bit tired or feel sleep deprived, I also don't need an alarm clock to wake me up,I exercises Alot and I live a very healthy life style so I AM worrying about it, Does this mean im sleeping enough?ps I sleep for 4 to 6 hours sometimes less sometimes more but im a very deep sleeper.